A system and method is disclosed for using an input data signal as a clock signal in a state machine of a radio frequency identification (RFID) tag. An output of a demodulator in the RFID tag is directly coupled to a clock input of the command state machine in the RFID state machine. The command state machine receives an edge detect signal directly from the input data signal and then immediately generates backscatter signals to begin a backscatter process. The edge detect signal may comprise a rising edge of a data symbol of the RFID protocol. The immediate initiation of the backscatter process reduces latency of the backscatter process in the RFID state machine.
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1. An apparatus for providing an edge detect signal to a command state machine of a state machine of a radio frequency identification (RFID) tag, wherein said apparatus comprises: a demodulator configured to demodulate a radio frequency signal to obtain a data signal, the demodulator having an output directly connected to a clock input of said command state machine in order to clock said command state machine using said data signal.
An RFID tag includes a demodulator that extracts a data signal from a received radio frequency signal. The demodulator's output is directly connected to the clock input of a command state machine within the RFID tag. This allows the data signal itself to drive the clock of the command state machine. This direct connection is implemented to avoid a separate clock signal.
2. The apparatus as set forth in claim 1 wherein said command state machine is configured to receive an edge detect signal from said data input signal and to use said edge detect signal to clock said command state machine.
The RFID tag from the previous edge detection description is further enhanced so that the command state machine uses an edge detect signal derived directly from the received data signal to trigger state transitions. The command state machine clocking relies on this rising or falling edge signal within the data.
3. The apparatus as set forth in claim 2 wherein said command state machine is configured to generate at least one backscatter signal when said command state machine receives said edge detect signal.
In the RFID tag featuring edge detection, the command state machine is configured to immediately generate at least one backscatter signal as soon as it detects an edge in the input data signal. This immediate backscatter response helps to reduce latency in the RFID tag's communication process.
4. The apparatus as set forth in claim 3 wherein said at least one backscatter signal comprises one of: a backscatter enable signal and a backscatter data signal.
Continuing the RFID tag's backscatter signal generation, the backscatter signal generated can be a backscatter enable signal to begin the backscatter process or a backscatter data signal containing the information.
5. The apparatus as set forth in claim 2 wherein said edge detect signal comprises a rising edge of an end of a data symbol within said data input signal.
In the RFID tag with command state machine clocking, the edge detect signal is specifically a rising edge at the end of a data symbol (representing a bit or other data unit) within the received data signal. The state machine uses these rising edges as clock triggers.
6. The apparatus as set forth in claim 5 wherein said data symbol comprises one of: a Zero symbol, a One symbol, and a Null symbol of a radio frequency identification (RFID) protocol.
Focusing on the RFID tag's data symbols, the data symbol that generates the edge detect signal can be a "Zero", a "One", or a "Null" symbol, as defined by the specific RFID protocol being used. These symbols form the alphabet for the RFID communication.
7. The apparatus as set forth in claim 2 : wherein said edge detect signal comprises a rising edge of an end of a data symbol within said data signal; and wherein said command state machine is configured to generate at least one backscatter signal when said command state machine receives said rising edge of said end of said data symbol.
In the RFID tag, the edge detection involves identifying a rising edge at the end of an RFID data symbol in the received data. The command state machine uses this rising edge as a clocking event, and in response to this clocking event, it generates one or more backscatter signals to begin or modify communication.
8. The apparatus as set forth in claim 7 wherein said at least one backscatter signal comprises one of: a backscatter enable signal and a backscatter data signal.
For the RFID tag with the rising edge backscatter signal generation, the backscatter signal generated can be either a backscatter enable signal (initiating the backscatter communication) or a backscatter data signal (containing the information to be transmitted via backscatter).
9. The apparatus as set forth in claim 7 wherein said data symbol comprises one of: a Zero symbol, a One symbol, and a Null symbol of a radio frequency identification (RFID) protocol.
In the RFID tag with the rising edge clocking, the data symbol in the received data signal represents a data bit transmitted using a specific RFID protocol. This symbol is defined as a "Zero," a "One," or a "Null" depending on the encoding used in that protocol.
10. A method comprising the steps of: demodulating a radio frequency signal using a demodulator in a radio frequency identification (RFID) tag to obtain a data signal; and providing said data signal from said demodulator to a clock input of a command state machine in said RFID tag in order to clock said command state machine using said data signal.
A method for operating an RFID tag involves first demodulating a received radio frequency signal using a demodulator to obtain a data signal. Then, this data signal is directly fed into the clock input of a command state machine within the RFID tag, effectively using the data signal itself to clock the state machine's operation instead of a separate clock.
11. The method as set forth in claim 10 further comprising the steps of: receiving in said command state machine an edge detect signal from said data input signal; and clocking said command state machine with said edge detect signal.
Further refining the method for an RFID tag, the command state machine also receives an edge detect signal derived from the data signal. The command state machine is clocked using this edge detection signal and performs transitions. This rising edge triggers state changes.
12. The method as set forth in claim 11 further comprising the step of: generating in said command state machine at least one backscatter signal when said command state machine receives said edge detect signal.
The method includes generating at least one backscatter signal by the command state machine as soon as the edge detect signal is received. This immediate response improves latency in the RFID tag's backscatter communication.
13. The method as set forth in claim 12 wherein said at least one backscatter signal comprises one of: a backscatter enable signal and a backscatter data signal.
In the backscatter method, the backscatter signal can be either a backscatter enable signal (to initiate the backscatter communication) or a backscatter data signal (containing the actual data to be transmitted via backscatter).
14. The method as set forth in claim 11 wherein said edge detect signal comprises a rising edge of an end of a data symbol within said data input signal.
In this method, the edge detect signal is specifically the rising edge of a data symbol located within the received data signal. The command state machine triggers from these rising edges.
15. The method as set forth in claim 14 wherein said data symbol comprises one of: a Zero symbol, a One symbol, and a Null symbol of a radio frequency identification (RFID) protocol.
Considering the method, the rising edge signal is triggered by a data symbol. The data symbol comprises of a "Zero," a "One," or a "Null" symbol as determined by the RFID communication protocol.
16. The method of claim 10 , wherein the demodulating and providing steps decrease latency in a state machine of the RFID tag, the state machine comprising the command state machine.
In this state machine of the RFID tag, demodulating and providing the data signal as a clock decreases the latency in the state machine. The data signal from the demodulator is directly connected to the command state machine, reducing the delays for data processing and backscatter signal transmission.
17. A radio frequency identification (RFID) tag, comprising: a command state machine; and a demodulator configured to demodulate a radio frequency signal to obtain a data signal, the demodulator having an output directly connected to a clock input of the command state machine in order to clock the command state machine using the data signal.
An RFID tag includes a command state machine. A demodulator extracts a data signal from a radio frequency signal, with the demodulator's output being directly connected to the clock input of the command state machine. Therefore, the data signal clocks the command state machine, removing the need for a dedicated clock source.
18. The RFID tag of claim 17 , wherein the command state machine is clocked by an edge detect signal in the data signal.
Expanding the description of the RFID tag, the command state machine is clocked by an edge detect signal found within the data signal instead of a specific clock signal.
19. The RFID tag of claim 18 , wherein the edge detect signal comprises a rising edge of an end of a data symbol within the data signal; and wherein the command state machine is configured to generate at least one backscatter signal when the command state machine receives the edge detect signal.
This invention relates to RFID (Radio Frequency Identification) tag technology, specifically improving the detection and processing of data signals within RFID communication systems. The problem addressed is the efficient and accurate detection of data symbols in RFID signals to enable timely and reliable backscatter responses from the tag. The RFID tag includes a signal processing circuit that generates an edge detect signal upon identifying a rising edge at the end of a data symbol within the received data signal. This edge detection mechanism ensures precise timing for command interpretation. The tag also features a command state machine that monitors the edge detect signal. When the state machine receives this signal, it triggers the generation of at least one backscatter signal, allowing the tag to respond to the received data symbol promptly. This ensures synchronized communication between the RFID reader and the tag, reducing errors and improving data transmission efficiency. The edge detection and state machine interaction enhance the tag's ability to process commands accurately, particularly in environments with signal noise or interference. The system is designed to work with various RFID protocols, ensuring compatibility and reliability across different applications. The invention focuses on optimizing the tag's response mechanism to improve overall RFID system performance.
20. The RFID tag of claim 18 , wherein the edge detect signal comprises a rising edge of an end of a data symbol within the data signal; and the data symbol comprises one of: a Zero symbol, a One symbol, and a Null symbol of an RFID protocol.
In the RFID tag, the edge detect signal is triggered by a rising edge. The rising edge is caused by the end of a data symbol in the data signal, where the data symbol is either a "Zero," "One," or "Null" symbol according to the RFID communication protocol.
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May 5, 2005
July 2, 2013
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